43 lines
836 B
C++
43 lines
836 B
C++
#include <cstdio>
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#include <algorithm>
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using namespace std;
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struct Node
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{
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int d,p;
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};
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Node roads[10001];
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int n,m;
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int sum;
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bool cmp(Node n1,Node n2)
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{
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return n1.p > n2.p;
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}
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int main()
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{
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while(scanf("%d %d", &n, &m), m!=0 || n!=0)
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{
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sum = 0;
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for(int i=0; i<n; i++)
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{
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scanf("%d%d", &roads[i].d, &roads[i].p);
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sum += roads[i].d*roads[i].p;
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}
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sort(roads, roads+n, cmp);
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for(int i=0; i<n; i++)
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{
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if(m > roads[i].d)
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{
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m -= roads[i].d;
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sum -= roads[i].d * roads[i].p;
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}
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else
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{
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sum -= m * roads[i].p;
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break;
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}
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}
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printf("%d\n",sum);
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}
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return 0;
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}
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